Remove low selective indexes

db/migrate/20181106135939_add_index_to_deployments.rb

@@ -8,20 +8,10 @@ class AddIndexToDeployments < ActiveRecord::Migration
   disable_ddl_transaction!
 
   def up
-    add_concurrent_index :deployments, [:project_id, :status, :id]
-    add_concurrent_index :deployments, [:project_id, :status, :iid]
     add_concurrent_index :deployments, [:project_id, :status, :created_at]
-    add_concurrent_index :deployments, [:environment_id, :status, :id]
-    add_concurrent_index :deployments, [:environment_id, :status, :iid]
-    add_concurrent_index :deployments, [:environment_id, :sha]
   end
 
   def down
-    remove_concurrent_index :deployments, [:project_id, :status, :id]
-    remove_concurrent_index :deployments, [:project_id, :status, :iid]
     remove_concurrent_index :deployments, [:project_id, :status, :created_at]
-    remove_concurrent_index :deployments, [:environment_id, :status, :id]
-    remove_concurrent_index :deployments, [:environment_id, :status, :iid]
-    remove_concurrent_index :deployments, [:environment_id, :sha]
   end
 end

db/schema.rb

@@ -833,15 +833,10 @@ ActiveRecord::Schema.define(version: 20181107054254) do
   add_index "deployments", ["deployable_type", "deployable_id"], name: "index_deployments_on_deployable_type_and_deployable_id", using: :btree
   add_index "deployments", ["environment_id", "id"], name: "index_deployments_on_environment_id_and_id", using: :btree
   add_index "deployments", ["environment_id", "iid", "project_id"], name: "index_deployments_on_environment_id_and_iid_and_project_id", using: :btree
-  add_index "deployments", ["environment_id", "sha"], name: "index_deployments_on_environment_id_and_sha", using: :btree
-  add_index "deployments", ["environment_id", "status", "id"], name: "index_deployments_on_environment_id_and_status_and_id", using: :btree
-  add_index "deployments", ["environment_id", "status", "iid"], name: "index_deployments_on_environment_id_and_status_and_iid", using: :btree
   add_index "deployments", ["environment_id", "status"], name: "index_deployments_on_environment_id_and_status", using: :btree
   add_index "deployments", ["id"], name: "partial_index_deployments_for_legacy_successful_deployments", where: "((finished_at IS NULL) AND (status = 2))", using: :btree
   add_index "deployments", ["project_id", "iid"], name: "index_deployments_on_project_id_and_iid", unique: true, using: :btree
   add_index "deployments", ["project_id", "status", "created_at"], name: "index_deployments_on_project_id_and_status_and_created_at", using: :btree
-  add_index "deployments", ["project_id", "status", "id"], name: "index_deployments_on_project_id_and_status_and_id", using: :btree
-  add_index "deployments", ["project_id", "status", "iid"], name: "index_deployments_on_project_id_and_status_and_iid", using: :btree
   add_index "deployments", ["project_id", "status"], name: "index_deployments_on_project_id_and_status", using: :btree
 
   create_table "emails", force: :cascade do |t|